Santiago fortress consisted of a tower and two small bastions that were connected by an earthen wall and a small house. These were surrounded by a wall with a gate that was made of Wood. 8 Cannon were deployed towards the sea and the fortress was manned on a regular basis with 4 men.
On the landside the castle was less well defended: no cannon were deployed there.
Near the landing site where the Dutch troops were gathering a Spanish guard post was situated. This post was manned by 6 soldiers and 4 Guaiqueri indians who were commanded by Alonso Garcia. As soon as they saw the Dutchmen disembarking they fled from their post to the surrounding woods. They did not even send a warning to the fortress.
When the 1½ hour bombardment of Santiago ceased Don Juan de Vargas sent some men East of the castle to see what was happening there. On their return these men met with most of the garrison, under the command of Don Bartolome de Vargas Machuca (the uncle of Juan), who had left the fortress for reasons that were unclear. Bartolome and some of his men returned to with Juan de Vargas to the fortress. Juan sent his man Mayorga for reinforcements to the city of Pampatar. On his way Mayorga met with Governor Villegas and after giving his message went to the trenches in the harbour. Governor Villegas sent 20 soldiers and 12 Guaiqueri bowmen to Santiago.
Meanwhile an advance party of Dutch soldiers immediately after disembarking went on its way to attack the fortress. This party of 10-20 men was led by Admiral Hendrikszoon himself. The advance party was too eager, however, and got cut off from the main force by Spanish soldiers commanded by Juan de Vargas. Juan also managed to split up the advance party. Some of them were forced to retreat a ways to wait for the main force. The others went on to attack the fortress. Juan de Vargas, Don Bartolome and a few men that were still in the castle fiercely defended it. During the attack Hendrikszoon lost his sword to Don Bartolome. When the Dutch soldiers finally captured and opened the gates, Don Bartolome and some of the soldiers abandoned it and went to join Governor Villegas who had just arrived with the reinforcements. Bartolome was fiercely berated for abandoning the fortress. Villegas personally commanded the Spanish soldiers he sent to Santiago in an attempt to retake it. The Dutchmen defended the fortress very well and when Villegas saw the main Dutch landing party coming from the east he abandoned the attempt.
Villegas was furious at the refusal of the soldiers, in the trenches of the harbour, to join him when he attacked Santiago despite several entreaties.